Category Archives for Hydraulic Circuits
Automatic Cylinder Reciprocating System
The hydraulic circuit shown in Fig. 1.8 produces continuous reciprocation of a double-acting cylinder using two sequence valves. Each sequence valve senses the completion of stroke by the corresponding build-up pressure. Each check valve and the corresponding pilot line prevent … Continue reading
Hydraulic Cylinder Sequencing Circuits
Hydraulic cylinders can be operated sequentially using a sequence valve. Figure 1.7 shows that two sequence valves are used to sequence the operation of two double-acting cylinders. When the DCV is actuated to its right-envelope mode, the bending cylinder (B) … Continue reading
Counterbalance Valve Application
A counterbalance valve (Fig. 1.6) is applied to create a back pressure or cushioning pressure on the underside of a vertically moving piston to prevent the suspended load from free falling because of gravity while it is still being lowered. … Continue reading
Control of a Single-Acting Hydraulic Cylinder
Figure 1.1 shows that the control of a single-acting,spring return cylinder using a three-way two-position manually actuated, spring offset direction-control valve (DCV). In the spring offset mode, full pump flow goes to the tank through the pressure-relief valve (PRV). The … Continue reading
Bleed-Off Circuit
Compared to meter-in and meter-out circuits, a bleed-off circuit is less commonly used. Figure 1.10 shows a bleed-off circuit with extend stroke control. In this type of flow control, an additional line is run through a flow-control valve back to … Continue reading
Meter-Out Circuit
Figure 1.9 shows a meter-out circuit for flow control during the extend stroke. When the cylinder extends, the flow coming from the pump into the cylinder is not controlled directly. However, the flow out of the cylinder is controlled using … Continue reading
Meter-In Circuit
Figure 1.8 shows a meter-in circuit with control of extend stroke. The inlet flow into the cylinder is controlled using a flow-control valve. In the return stroke, however, the fluid can bypass the needle valve and flow through the check … Continue reading
Sequencing Circuits
In many applications, it is necessary to perform operations in a definite order. Following is one of several such circuits. The components of the system are as follows. A : Reservoir and Filter ; B : Hydraulic Pump ; C … Continue reading
Regenerative Reciprocating Circuit
Conventional reciprocating circuits use a four-way directional valve connected directly to a cylinder. In a regenerative reciprocating circuit, oil from the rod end of the cylinder is directed into the cap end to increase speed, without requiring to increase pump … Continue reading
Reciprocating Cylinder with Automatic Venting at End of Cycle
A reciprocating cylinder drive is a very common hydraulic system. In systems where it is not necessary to hold pressure at the end of a cycle, it is desirable to unload the pump by automatically venting the relief valve, to … Continue reading